Star Trek: Insurrection

Star Trek IX: Insurrection is the ninth Star Trek movie. Direct by Jonathan Frakes, and featuring the Star Trek: The Next Generation cast.

Warning: Wikipedia contains spoilers

During a diplomatic mission, the USS Enterprise-E receives a communication that Commander Data has gone berserk during an observation mission at the Ba'ku[?] homeworld.

After capturing and fixing Data they return to the Ba'ku village on the planet surface to find what caused him to malfunction. They find a Federation ship which is basically a holodeck of the Ba'ku's homeworld, apparently so the Ba'ku can be unwittingly relocated without their knowledge.

It's discovered by Captain Picard and his crew that the planet has fountain of youth qualities which the Federation and the Son'a[?] wish to harvest. However, harvesting the particles would cause the planet to become uninhabitable.

Captain Picard and the Enterprise crew (including Worf) return to the planet surface to prevent the relocation of the Ba'ku. When Picard is captured by the Son'a and Federation, he reveals to the Federation Admiral that the Son'a are actually Ba'ku who left the planet years ago and are simply out for revenge.